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Anomalous thermal maturities caused by carbonaceous sediments
Author(s) -
Pollack HENRY N.,
Cercone KAREN ROSE
Publication year - 1994
Publication title -
basin research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.522
H-Index - 83
eISSN - 1365-2117
pISSN - 0950-091X
DOI - 10.1111/j.1365-2117.1994.tb00074.x
Subject(s) - maturity (psychological) , geology , sedimentary rock , organic matter , geochemistry , structural basin , mineralogy , coal , sedimentary basin , thermal conductivity , thermal , range (aeronautics) , petrology , geomorphology , chemistry , psychology , developmental psychology , materials science , organic chemistry , composite material , thermodynamics , physics , meteorology
Sedimentary rocks such as coal and carbonaceous mudstone which contain abundant carbonaceous matter are characterized by thermal conductivity much lower than that exhibited by other common rock types, by a factor of 5–10. As a result, temperature gradients in such sediments can range up to 0.25 °Cm ‐1 even under conditions of average heat flow. When such steep gradients extend over a significant sedimentary thickness, temperatures of underlying rock units are elevated, causing both organic and inorganic phases to record what seem to be anomalously high levels of thermal maturity. This carbonaceous blanket insulating effect may help to explain unusual levels of maturity observed at shallow depths in the Appalachian Basin, Michigan Basin and other regions of the world with significant carbonaceous strata.